Bigboat
I found a ferrite transformer that I think is the same size like the one you used. It fits into the holes on the board just like a glove (not OJ glove, though ). Do I make 400 windings or do I use a wire 16.2m as mentioned on this thread before?

Also, is the size of the wire important? I have some 0.13mm wire. Can I use it for the 400 winding coil?

Yoram